Rheostat-lamp socket



Patented May 17, 1932 UNITED STATES CARL L. WEICHELT, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO WIRT COMPANY,

PATENT OFFICE RHEOSTAT-LAMP SOCKET Application filed February 10, 1930.

This invention relates to rheostat-lamp sockets, wherein a variable resistance is employed to regulate the flow of current through the filament of an associated lamp so that the intensity of illumination or candle power of the lamp may be varied and is herein illustrated as embodied in a lamp socket adapted for association with a lighting fixture as, for example, of the wall-bracket type.

An object of the invention is to provide an improved rheostat-lamp socket-in which the parts thereof are so constructed as to enable them'to be cheaply manufactured and easily assembled into a compact, durable, reliable and otherwise satisfactory device.

The invention contemplates the provision of a resistance unit, with which is associated a screw-threaded receptacle adapted to receive an electric lamp, there being provided intermediate the receptacle and the resistance unit a pair of suitable supports, which serve to retain the resistance unit and the screwthreaded receptacle in a proper relation and to support a rotatable switch member, by which the filament circuit may be opened and closed and by which the resistance element of said unit may be so connected in thatvcircuit as to vary the intensity of illumination or candle power of the lamp.

, Other objects and advantages of the invention will become apparent from the following description taken in connection with the accompanying drawings, in which Figure 1 is a side elevation of a rheostatlamp socket embodying this invention, shown partly in section; Figure 2 is a side elevation of the device as viewed from the left in Figure 1, the protective acket being shown in section; Figure 3 is a side elevation of the socket as viewed from the left in Figure 2, the protective jacket being also shown in section; Figure 4 is an enlarged vertical, central, sectional view taken on line 44 of Figure 3 with the protective jacket removed and showing the rotatable switch member in open circuit position; Figure 5 is a view similar to Figure 4 only in so far as the rotatable switch member and the screw-threaded receptacle are concerned and showing diagrammatically the relation of the resistance Serial No. 427,167.

element to the several contact elements with which the rotatable switch. member is adapted to cooperate; Figure 6 is a transverse sec tional view of the rotatable switch member so positioned with respect to its associated contact elements or terminals as to introduce into the filament circuit the entire resistance element; Figure 7 is a view similar to that of Figure 6, and showing the rotatable switch member so positioned as to render effective only a portion of the resistance element in the filament circuit; Figure 8 is a View similar to that of Figures 6 and 7, and showing the rotatable switch member so positioned as to render the entire resistance element ineffective in the filament circuit; and Figure 9 is a perspective view of an arcuate contact segment carried by the rotatable switch member.

The device herein shown as embodying the invention comprises a resistance unit 10, a switch unit 11 and a lamp socket unit 12, all cooperatively related in a novel, compact, durable, reliable and otherwise satisfactory structure.

The resistance unit 10 includes a body or support 13 of suitable insulating material, such as porcelain, and carries on its peripheral surface a resistance element 14 made up of a plurality of turns of suitable resistance wire. One end of the resistance element is connected to a conductor strip or lug 15 located in a terminal-receiving pocket 16, formed in the body 13 near the lower end thereof, the other end of the resistance element being connected to the base portion 17 of a spring contact element or arm 18 which is secured to the top of the body by a tie bolt 19. This tie bolt projects downwardly through the body 13 into a pocket 20 formed therein, and passes through the outer end of the base portion 21 of a spring contact element or arm 22 which projects upwardly through a passage 23 formed in the body, the base portion of such contact element being connected to the resistance element 14 intermediate the ends thereof for the purpose hereinafter more particularly described. It is to be noted that the tie bolt 19, which serves to anchor the contact elements 18 and 22 to the body 18, is insulated from the former of these contacts by an insulating washer 2 1, one portion of which is located within the opening of the base portion 17 through which the tie bolt passes and the other portion of which is confined between that base portion and the head of the tie bolt.

Pl'Ojecting downwardly through the body 13 is a tie. bolt 27, the lower end of which is connected, as by screw threads, to an angularly shaped terminal 28, to which a lead-in conductor may be connected by a screw 29 carried by one leg thereof. The tie bolt 27 passes through the conductor strip or lug 15 and serves to maintain the terminal 28, by reason of its screw thread engagement therewith, in contact with such lug. Between the body 13 and the head of the tie bolt 27 is confined one end of a spring contact element or arm 30 which is electrically connected by the latter to the terminal 28 so that the whole of the re sistance element may be short circuited, when maximum current is desired in the filament circuit, as will hereinafter more clearly apear. I The switch unit 11 includes a pair of spacedapart metallic brackets 31, each of which is provided with upper and lower foot portions 3-32 and 33, respectively. The brackets 31 are secured to theresistance unit 10 by tie rods 34 and 35 extending through suitable openings formed in the body 13 and having screwthreaded engagement with the foot portions of the brackets 31, the tie rod 85 serving to connect to the body 13 an angular shaped terminal 36 which is located within a terminalreceiving pocket 37 formed in the body and is provided with a screw 38 by which a leadin conductor may be connected thereto.

Each of the brackets 31 is provided intermediate its ends with an opening 39, the openings so provided being in alignment with each other and adapted to receive the reduced ends or bearing portions of a rotatable switch member 40 of suitable insulating material. It is to be noted that the switch member 40 is retained against longitudinal movement intermediate the bracket members 31 by reason of the shoulder portions 42 formed thereon adjacent the ends thereof. Intermediate the ends of the switch member 40, is formed a circumferential groove 43, within which is carried an arcuate shaped short-circuiting segment or contact 44. This contact 14 is bent at its opposite ends into gripping engagement thereof, to which is connected a tubular shaft 50, provided at its outer end with a handwheel 51, the tubular shaft being locked against rotation with respect to the bolt -17 by a set screw 53, and the bolt 47 being retained against rotation with respect to the switch member 40 by the nut 18. It is with the arcuate short-circuiting contact 44 that the resistance contact terminals 18, 22 and 30 are adapted to cooperate so that the filament circuit may be opened and closed and so that the resistance element 14 may be so connected in that circuit as to vary the intensity or candle power of the lamp, as will hereinafter more clearly appear.

The lamp socket unit 12 includes an outer screw-threaded shell or receptacle 55, into which an ordinary electric lamp is ada ted to be screwed, a portion of the bottom 0 the shell being cut away so as to provide an opening 56 and leave adjacent thereto a pair of inwardly projecting wings 57 and 58, to

which is secured an insulating contact-supporting disc 61. The wing 57 is provided .with a lug 59 which projects through the disc 61 and is bent down into engagement therewith. This disc 61 is held in position by a pair of screws 62 and 63, the former of which passes through the wing 58 and maintains screw-thread engagement with the upper foot portion 32 of one of the brackets 31. The other screw 63 passes through the lug 5.9 and the wing 57 and is maintained in screwthread engagement with the upper foot portion 32 of the other bracket 31, the screw being of such length that it projects a substantial distance through such foot portion so as tofo'rma stop 64, adapted to cooperate with an outwardly projecting abutment 65 carried by the switch member 40 and serving to limit rotation of that member in either direction to substantially 180. Secured to the disc 61. as by an eyelet 67, is a. lamp socket contact 68, which is bent back upon itself to provide a spring contact arm or element 69. adapted to cooperate with the short-circuiting contact 44 in a manner hereinafter more particularly described. This socket contact 68 projects upwardly through a. slot 70 formed in the supporting disc 61 and is bent downwardly so as to form a spring contact arm 71, having at one end thereof a raised portion adapted to engage the central contact of an ordinary electric lamp when such is screwed into the shell 55.

The socket herein shown as embodying the invention is particularly adapted for use 3:;

with lighting fixtures, as, for example. of the wall-bracket type, and to provide for its ready association with such fixtures a suitable screw-thread'ed connecting member 73 may be employed. Projecting through a longitudinal opening formed in the body 13, is a tie bolt or screw which engages one leg 75 of the connecting member 73 and serves to hold such member in position for attachment to a lighting fixture. The lamp socket hereinshown being particularly adapted for use with'lighting fixtures of the type mentioned,

, is'provi'ded -with.' a tubular protective casing 75, which surrounds the screw-tln'caded shell 55 and the switch unit 11, the wall of the casing'being formed with a slot 76 adapted to accon'nnodate the tubular shaiit 50.

hen the switch member all) is positioned as shown in Figuresl to 5 inclusive, the filament circuit is open inasmuch as the arcuate contact 44 then engages no one of the contact members '18, 22 and 30. By moving the switch member-'40 to its position shown in Figure 6, engagement of the contact 1-4 with the contact 18 only is efi'ected, with the result that the filament circuit is established throughthe terminal 36, tie rod 35, the bracket 31 engaged thereby, the screw-threaded -shell -55,'(the outer contact, filament, and central =contact of the electric lamp, not shown) the lamp socket contact ($8, shortcircuiting contact .44, contact arm 18, the whole of the resistance element 14, the lug or conductor strip and terminal 28, it being noted that a short or direct conducting path is provided by the short-circuiting contact it from the lamp socket central contact (38 and the resistance element. Upon moving the switch member 40 to its position shown in Figure 7 in which position the contact 44 engages'the contact arms 18 and 22, a portion of the resistance element, namely. the wand ings thereof intermediate its point of: connection with the base portion 17 of the contact arm 18 and its point of connection with thebase portion 210i? the contact arm 22, is short circuited through the contact 4-11 in engagement with said arms 18 and 22, but the short circuiting contact 4&1 establishes a direct conducting path between the lamp socket contact 68 and the resistance arm 22, with the result that only a portion of the resistance element 1%, namely, the windings thereof intermediate its point of connection with the lug l5 and the base portion 21 ot the contact arm 22, is rendered effective in the fi ament circuit. By rotating the switch member i l to its position shown in Figure 8, engagement of the contact 44; with the contact is established, with the result that the whole of the resistance element 1% is short circuited through the contact 44 in engagement with the arms 18 and 30. but the filament circuit is completed from the contact 68 to the terminal 28 through the short or direct conducting path provided by the short-circu t na' contact 44; in conjunction with the arm 30 and the tie bolt 27.

From the above it is apparent that the switch member may be actuated to open the filament circuit, to render the whole of the resistance element 14 elfective and thereby produce a minimum voltage drop across the lamp filament, to render only a portion of such resistance element effective and thereby produce only a corresponding voltage drop across the lamp filament circuit, and to short circuit the entire resistance element when maximum voltage across the lamp filament'is desired.

Although the invention is herein shown as embodied in a lamp socket particularly adaptcd for use with lighting fixtures, as, -tor example, of the wall-bracket type, it will be understood that the invention may be embodied in lamp sockets 01' other types, and that various changes may be made without departing from the spirit of the invention or the scope of the following claims.

\Vhat is claimed is:

1. A rheostat-lamp socket comprising a lamp socket having an inner and an outer contact, a body carrying a resistance element, a pair of brackets located intermediate the lamp socket and the body and securing the same in axial alignment with one another, terminals for the resistance element extending from that end of the body connected to the brackets, rotary switching means journalled in the brackets and carrying an arcuate shortcircuiting contact cooperativdy positioned relatively to one of said lamp socket contacts and the resistance terminals to provide a direct conducting path upon rotation of the switching means between said one of said lamp socket contacts and the respective resistance terminals, and lead-in terminals, one in electrical connection with the resistance element and the other in electrical connection with the other of said lamp socket contacts.

A rheostat-lamp socket comprising a lamp socket having an outer conductive shell and a central contact, a body carrying a resistance element, a pair of brackets located intermediate the lamp socket and the body and securing the same in axial alignment with one another, at least one of said brackets being in electrical connection with the lamp socket shell, terminals for the resistance element extending from the inner end of the body, rotary switching means journalled in the brackets and carrying an arcuate short-circuiting member cooperatively positioned relatively to the lamp socket central contact and the resistance terminals to provide a direct conducting path upon rotation of the switching means he (i tween the lamp socket central contact and the respective resistance terminals, and lead-in terminals on the body, one in electrical connection with the resistance element and the other in electrical connection with the bracket electrically connected to the outer conductive shell.

3. A rheostat-lamp socket comprising a lamp socket having an inner and an outer contact, an insulating body having a resistance element wound on its periphery, a pair of spaced brackets located intermediate the lamp socket and the body and securing the same in axial alignment with one another, contact arms extending from the inner end of the body, means for electrically connccting predetermined points of the resistance element to the contact arms, rotary switching means journalled in the brackets and including an arcuate short-circuiting contact cooperatively positioned relatively to one of said lamp socket contacts'and the resistance contact arms to provide a direct conducting path upon rotation of the switching means between said one of said lamp socket contacts and the respective resistance contact arms, and lead-in terminals, one in electrical connection with the resistance element and the other in electricalconnection with the other of said lamp socket contacts.

4. A rheostat-lamp socket comprising a lamp socket having an inner and an outer contact, an insulating body having a resistance element at its periphery, a pair of spaced brackets located intermediate the lamp socket and the body and securing the same in axial alignment with one another, switching means journalled in said brackets and including an arcuate short-circuiting contact, contact arms extending from the inner end of the body in an axial plane with the short-circuiting contact to cooperate with the latter, means for establishing electrical connection from predetermined points of the resistance element to said contact arms, another contact arm in electrical connection with one of said lamp socket contacts and extending from the inner end of the socket to also cooperate with the short-circuiting contact, the latter providing upon rotation of the switching means a direct conducting path between the contactarm electrically connected to said one of said lamp socket contacts and the respective contact arms electrically connected to the resistance element, and lead-in terminals, one in electrical connection with the resistance element and the other in electrical connection with the other of said lamp socket contacts.

5. A rheostatdamp socket comprising a lamp socket having an inner and an outer contact, an insulating body having a resistance element on its periphery, said body being provided with a cut-away portion in its outer peripheral surface, a pair of spaced brackets located intermediate the lamp socket and the body and securing the same in axial alignment with one another, switching means ournalled in said brackets and including an arcuate short-circuiting contact, terminal contact arms for said resistance extending from the inner end of the body in an axial plane with the short-circuiting contact, means in part located in said cut-away portion and in part extending through the body for connecting the resistance element at a predetermined point to a terminal arm, another contact arm electrically connected to one of said lamp socket contacts and extending from the inner end of the socket to also cooperate with the short-circuiting contact,'the latter providing upon rotation of the switchin means a direct conducting path between t 0 contact arm electrically connected to said one of said lamp socket contacts and the respective resistance terminal contact arms, and lead-in terminals, one in electrical connection with the resistance element and the other in electrical connection with the other of said lamp socket contacts.

v6. A rheostat-lamp socket comprisin a lamp socket having an outer conductive siell and a central contact, an insulating body having a resistance element wound on its periphery, a pair of spaced brackets located intermediate the lamp socket and the body and securing the same in axial alignment with one another, switching means ournalled in said brackets and including a short-circuiting contact cooperating with the lamp socket central contact, contact arms extending from the inner end ofv the body in an axial plane with the shortcircuiting contact to also cooperate withthe latter, securing devices extending through the body in the same axial plane for electrically connecting predetermined points of the resistance element to the contact arms, said short-circuiting contact providing upon rotation of the switching means a direct conducting path between the lamp socket central contact and the respective contact arms, one of said securing devices carr ing a leadin terminal on the body, and anot ler securing device extending through the body securing a bracket to the latter and also carrying a leadin terminal on the body.

In testimony whereof, I have aflixed my signature to this specification.

CARL L. WE ICHELT. 

